Network Working Group L. Walleij Request for Comments: 3534 The Ogg Vorbis Community Category: Standards Track May 2003
The application/ogg Media Type
Status of this Memo
This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved.
Abstract
The Ogg Bitstream Format aims at becoming a general, freely-available standard for transporting multimedia content across computing platforms and networks. The intention of this document is to define the MIME media type application/ogg to refer to this kind of content when transported across the Internet. It is the intention of the Ogg Bitstream Format developers that it be usable without intellectual property concerns.
Conventions used in this Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC2119 [2].
1. The Ogg Bitstream Format
The Ogg Bitstream format has been developed as a part of a larger project aimed at creating a set of components for the coding and decoding of multimedia content (codecs) which are to be freely available and freely re-implementable both in software and in hardware for the computing community at large, including the Internet community.
Raw packets from these codecs may be used directly by transport mechanisms that provide their own framing and packet-separation mechanisms (such as UDP datagrams).
One such framing and content-separation mechanism is the real-time transport protocol (RTP). RTP allows the streaming of synchronous lossy data for broadcasting and similar purposes. If this function is desired then a separate RTP wrapping mechanism should be used. A wrapping mechanism is currently under development.
For stream based storage (such as files) and transport (such as TCP streams or pipes), Ogg codecs use the Ogg Bitstream Format to provide framing/sync, sync recapture after error, landmarks during seeking, and enough information to properly separate data back into packets at the original packet boundaries without relying on decoding to find packet boundaries. The application/ogg MIME type refers to this kind of bitstreams, when no further knowledge of the bitstream content exists.
The bitstream format in itself is documented in [1].
2. Registration Information
To: ietf-types@iana.org
Subject: Registration of MIME media type application/ogg
MIME media type name: application
MIME subtype name: ogg
Required parameters: none
Optional parameters: none
Encoding Considerations:
The Ogg bitstream format is binary data, and must be encoded for non-binary transport; the Base64 encoding is suitable for Email. Binary encoding could also be used.
Security Considerations:
As the Ogg bitstream file is a container format and only a carrier of content (such as Vorbis audio) with a very rigid definition (see [1]), this format in itself is not more vulnerable than any other content framing mechanism. The main security consideration for the receiving application is to ensure that manipulated packages can not cause buffer overflows and the like. It is possible to encapsulate even executable content in the bitstream, so for such uses additional security considerations must be taken.
Ogg bitstream files are not signed or encrypted using any applicable encryption schemes. External security mechanisms must be added if content confidentiality and authenticity is to be achieved.
Interoperability considerations:
The Ogg bitstream format has proved to be widely implementable across different computing platforms. A broadly portable reference implementation is available under a BSD license.
The Ogg bitstream format is not patented and can be implemented by third parties without patent considerations.
Published specification:
See [1].
Applications which use this media type:
Any application that implements the specification will be able to encode or decode Ogg bitstream files. Specifically, the format is supposed to be used by subcodecs that implement, for example, Vorbis audio.
Additional information:
Magic number(s):
In Ogg bitstream files, the first four bytes are 0x4f 0x67 0x67 0x53 corresponding to the string "OggS".
File extension: .ogg
Macintosh File Type Code(s): OggS
Object Identifier(s) or OID(s): none
Person & email address to contact for further information:
Questions about this proposal should be directed to Linus Walleij <triad@df.lth.se>. Technical questions about the Ogg bitstream standard may be asked on the mailing lists for the developer community. <http://www.xiph.org/archives/>
Intended usage: COMMON
Author/Change controller:
This document was written by Linus Walleij <triad@df.lth.se>. Changes to this document will either be handled by him, a representative of the Xiph.org, or the associated development communities.
The Ogg bitstream format is controlled by the Xiph.org and the respective development communities.
3. Security Considerations
Security considerations are discussed in the security considerations clause of the MIME registration in section 2.
4. Normative References
[1] Pfeiffer, S., "The Ogg encapsulation format version 0", RFC 3533, May 2003.
[2] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC2119, March 1997.
5. Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any effort to identify any such rights. Information on the IETF's procedures with respect to rights in standards-track and standards-related documentation can be found in BCP-11. Copies of claims of rights made available for publication and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementors or users of this specification can be obtained from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights which may cover technology that may be required to practice this standard. Please address the information to the IETF Executive Director.
6. Author's Address
Linus Walleij The Ogg Vorbis Community Master Olofs Vag 24 Lund 224 66 SE
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